Research

Politicians, pundits, and ordinary citizens frequently argue that private money has an outsized influence on U.S. politics. Yet research on the effect of money on politicians' behavior finds limited effects, especially on voting behavior. I construct a formal model to show that these limited effects may be an artifact of the institutional powers of agenda setters in Congress, and the strategic nature of the data generating process. The model predicts that under general conditions, vote buying against proposals can occur with no vote held, and that vote buying is most likely when uncertainty is high, the interest group and agenda setter are extreme, and the pivotal legislator is moderate. I argue that these conditions held during the 2021 negotiations over the Build Back Better Act. Using a synthetic control design, I test whether the swing voters in the Senate received more campaign contributions than they would have otherwise, finding evidence consistent with the model.

Spatial models of agenda setting are central to the study of legislative politics, yet they typically abstract from the influence of interest groups. To address this gap, I unify the classical one-dimensional agenda setting framework with models of vote buying, starting with one group and extending to two moving sequentially. Anticipating the groups' responses, the agenda setter strategically adjusts proposals to take advantage of support or to preempt opposition. This unification generates a number of insights into interest groups' behavior, and how their influence affects gridlock, coalition size, and policy moderation. Most notably, the model offers a new explanation for supermajority coalitions: rather than arising from competition between vote buyers, supermajorities emerge because the proposer biases policy toward the opposing group to reduce the likelihood of opposition. Contrary to previous theories, coalitions can be larger when there is just a single interest group than when there are two. 

Ansolabehere, de Figueiredo, and Snyder (2003) famously argue that most money in politics is motivated by consumption rather than investment, citing evidence that campaign contributions have little effect on legislators’ voting behavior. Because this argument has served as an influential benchmark in the study of money in politics, we revisit it using updated data and new theoretical tools. First, we show that a comparable analysis using more recent data reveals a modest but statistically significant relationship between contributions and vote choice. Second, we use simulations from a formal model of vote buying with an endogenous legislative agenda to demonstrate that standard empirical approaches may systematically underestimate the effects of contributions. Third, we show that the challenge of inference becomes even more difficult when contributions are driven by a mix of expressive and instrumental motives. Finally, we review theoretical arguments that help explain why contributions might appear low even when they reflect attempts to influence policy. Together, these findings suggest that the influence of organized interests may be more substantial, and more difficult to detect, than the dominant interpretation of the early evidence implied.

Do firms earn returns to their political campaign contributions? A growing empirical literature uses close-election regression discontinuity designs (RDDs) to answer this question. Because these designs are local to close elections, extrapolation requires a theory of how firms’ returns vary across electoral environments. A common intuition is that firms’ returns ought to be high in close elections because this is exactly when contributions are most valuable to a politician. This intuition, however, neglects how the donor pool changes with electoral competitiveness. I construct a model of quid pro quo campaign contributions, showing that average returns may be lowest when elections are close, in which case close election RDDs would be a relatively weak test of the quid pro quo theory.